1. Field of the Invention
This present invention relates to an improved method and apparatus for data regeneration in asynchronous network communication.
2. Description of Prior Art
Communication networks which transmit data over wire or fiber are limited in the distance in which the data may be transmitted and successfully recovered at the receiving end. The physical properties of the transmission media as well as the properties of the data transmitter and data receiver determine the maximum communication distance, 1, between transmitter and receiver. In networks that do not implement any type of data repeater or regeneration, the length, 1, is the maximum length for the entire network.
Prior art data repeaters have been utilized in long communication lines to increase the distance between the transmitter and receiver. The repeaters typically work by amplifying the signal. Direction sensing bi-directional repeaters are known in the art and are described, for example, in an article by Gary Murdock and John Goldie entitled Build a Direction-Sensing Bidirectional repeater, Vol. 37, No. 10, Electronic Design, May 11, 1989, reprinted in National Semiconductor AN-702. These prior art repeaters, however, only amplify the signal and do not regenerate the data as new, clean data. Therefore, if there is any distortion or noise in the data, it is not corrected by the repeater.
To solve the problem of distorted data, various methods of asynchronous network communication provide for data regeneration at each node of the communication network which typically involves the buffering of a portion of the data in the receiving node before regenerating and retransmitting the data to the next node of the network. The current methods of data buffering require that the entire message (i.e., one to m bytes of data) or at a minimum, one byte of date (8 data bits plus a start and stop bit) be buffered by the receiving node before the data is regenerated and retransmitted to the next node in the communication network. By using data regeneration at each of the network nodes, n, the overall network transmission media length can be increased such that an overall length of n.times.1 can be achieved.
These prior art repeaters and data regenerators fail to accomplish the objects set out below which include significantly reducing the data buffering to one half bit of data, and therefore significantly increasing the network throughput, while at the same time providing the n.times.1 overall network transmission media length.